1. Field of the Invention
The present invention generally relates to scan engines, more particularly, relates to a scan engine with a built-in auto trigger.
2. Description of the Related Art
Scan engines used for scanning symbols having data identifying characteristics such as barcodes are known. Further, manual triggers used in scan systems are known. For example U.S. Pat. No. 5,329,106 to Hone et al describes a handle-less barcode scanning system with a manually actuated trigger on the printed circuit board.
Scanning systems with separate trigger devices are known. As shown in FIG. 1, a prior art auto trigger optical system is shown. A separate and independent auto trigger subsystem to the scanning system is shown. A separate light emitting diode (LED) used for triggering purposes is suitably positioned within a hand held barcode code scanner. The scanner contains a separate scan engine therein. The trigger LED emits light, which when reflected from a desired barcode type, is detected or received by a photo detector (PD). The reflected light input to the PD is transformed into an electronic signal, which in turn is processed by a processor (not shown) causing the scan engine to initiate desired barcode scanning.
FIG. 2 is a block diagram of the prior art scanning system showing a separate path for the trigger subsystem 6. A separate barcode PD and a separate trigger PD are used for triggering and barcode reading respectively. Note that a switch 8 is used to switch between a trigger subsystem 6 and the barcode scanning system.
As can be seen, known systems use separate and independent triggering optical components. The separate and independent component each has dimension and takes up space. For example, the components may be placed besides the barcode scanning optical path. Further, an extra circuit board may be required for placing the component and the wirings associated therewith. More components necessarily lower the life span of the scanner in that the failure of one component disrupts the operation of the entire system.
Therefore, it is desirable to have a scan system free of the separate and independent triggering optical components described supra. It is further desired to have the scan system with a triggering function achieved efficiently using the existing components of a scan engine.